Hearing aids are wearable hearing apparatus used to provide assistance to those with hearing defects. To meet the numerous individual requirements, different designs of hearing aid, such as behind-the-ear (BTE) hearing aids, receiver-in-the-canal) (RIC) hearing aids and in-the-ear (ITE), hearing aids, e.g. also Concha hearing aids or canal hearing aids (ITE, CIC), are provided. The hearing aids typically listed are worn in the outer ear or in the auditory. In addition bone-conduction, implantable or vibro-tactile hearing aids are also available on the. In such cases the damaged hearing is stimulated mechanically or electrically.
Hearing devices are wearable hearing apparatuses which are used to assist the hard-of-hearing. In order to accommodate numerous individual requirements, various types of hearing devices are available such as behind-the-ear hearing devices (BTEs), hearing device with an external receiver (RIC: receiver in the canal) and in-the-ear hearing devices (ITE), for example also concha hearing devices or completely-in-the-canal hearing devices (ITE, CIC). The hearing devices listed as examples are worn on the outer ear or in the auditory canal. Bone conduction hearing aids, implantable or vibrotactile hearing aids are also available on the market. In these devices damaged hearing is stimulated either mechanically or electrically.
The key components of hearing devices are principally an input converter, an amplifier and an output converter. The input converter is normally a receiving transducer e.g. a microphone and/or an electromagnetic receiver, e.g. an induction coil. The output converter is most frequently realized as an electroacoustic converter e.g. a miniature loudspeaker, or as an electromechanical converter e.g. a bone conduction hearing aid. The amplifier is usually integrated into a signal processing unit. This basic configuration is illustrated in FIG. 1 using the example of a behind-the-ear hearing device. One or more microphones 2 for recording ambient sound are built into a hearing device housing 1 to be worn behind the ear. A signal processing unit 3 which is also integrated into the hearing device housing 1 processes and amplifies the microphone signals. The output signal for the signal processing unit 3 is transmitted to a loudspeaker or receiver 4, which outputs an acoustic signal. Sound is transmitted through a sound tube, which is affixed in the auditory canal by means of an otoplastic, to the device wearer's eardrum. Power for the hearing device and in particular for the signal processing unit 3 is supplied by means of a battery 5 which is also integrated in the hearing device housing 1.
The centering of receivers of RIC (receiver in the canal; hearing aid with external receiver) depends on a number of circumstances. Mostly the centering depends on the shape of the auditory canal. Provided there is a sufficiently large amount of space in the auditory canal, the centering of the receiver also depends on an equilibrium between the forces exerted on the receiver by the rest of the hearing system and the rigidity of the earpiece. The current normal standard receivers are too soft to be able to guarantee a sufficient centering, if the structure of the auditory canal is difficult and/or if high forces from the rest of the hearing system act on the receiver. Such problems occur in particular with what are known as cymba hearing devices, which need the earpiece in the auditory canal as an essential support point so that they can be worn stably on the ear or in the cymba. With conventional components the forces exerted on the receiver are often so high that it is pressed into the auditory canal wall. If the receiver is located well away from the center axis of the auditory canal however, i.e. it is not centered, this leads to problems for the wearer, especially to inflammation of the auditory canal wall.
In addition an eccentrically arranged receiver can also have noticeable acoustic effects. In particular receivers that do not lie precisely in the center of the auditory canal frequently lead to increased feedback. The result of this is that the amplification of the hearing loss has to be reduced. Compensation for the hearing loss is then not at its optimum.
Previously two different types of closed standard earpieces have been used. The type used depends on the receiver type employed. With smaller receivers (45 and 55 dB) only an output power and amplification that is too low at high frequencies is possible with normal earpieces. In addition the closed standard earpieces lead to so-called occlusion effects.